[SI-LIST] Re: AW: Control Impedance testing
- From: "Salkow, Steven" <steven.salkow@xxxxxxxx>
- To: "'Havermann, Gert'" <Gert.Havermann@xxxxxxxxxxx>, "'si-list@xxxxxxxxxxxxx'" <si-list@xxxxxxxxxxxxx>
- Date: Fri, 11 Sep 2009 18:36:44 -0600
Coupons are a practical way to audit Trace impedance. There should be test
coupons for every signal layer and every different type: i.e. differential and
single ended as required. Most fabricators can now generate the test coupons
too. If going this way, have them serialised same as board and note lot codes
for tracking. See IPC 2221/2222 for more info. Your fabricator knows all about
this - ask for a run down.
Steven Salkow
Lockheed Martin
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Havermann, Gert
Sent: Sunday, August 30, 2009 11:54 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] AW: Control Impedance testing
Dear Liao,
there are some PCB maker out there with the capability and willingness to test
all, or selected traces of your board. Of coarse you have to pay for this
service, as well as you have to pay for very tight impedance control. For mass
production this is not the way to go. You have to make shure that the design
works within all production variations. For special test cards, thats another
story. We found a PCB maker in Germany for such test boards, and they guaratee
a 6% tolerance for prototype volumes and test most of the traces.
Unfortunately, they can only test single ended, thus you have to specify both
impedances, and they will only guaratee the single ended to come out right.
Let me know if you would like the contact data.
BR
Gert
--------------------------------------------------------------------------
Absender ist HARTING Electronics GmbH & Co. KG; Sitz der Gesellschaft:
Espelkamp; Registergericht: Bad Oeynhausen; Register-Nr.: HRA 5596; persönlich
haftende Gesellschafterin: HARTING Electronics Management GmbH; Sitz der
Komplementär-GmbH: Espelkamp; Registergericht der Komplementär-GmbH: Bad
Oeynhausen; Register-Nr. der Komplementär-GmbH: HRB 8808; Geschäftsführer:
Torsten Ratzmann
-----Ursprüngliche Nachricht-----
Von: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] Im
Auftrag von BO-LIAO
Gesendet: Sonntag, 30. August 2009 14:09
An: si-list@xxxxxxxxxxxxx
Betreff: [SI-LIST] Control Impedance testing
Dear Sir,
My PCB supplier doesn't test control impedance on actual board. They said
control impedance is measured on test coupon.
Please advice if it is realistic and reliable to use the test coupon measured
impedance?
Is this an industry norm, or standard?
Thank you.
Best regards,
Liao Bo
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